We have recently learned more about a bug which is driven by large inventories. In working on fixing the bug, we believe we have learned how to prevent it.
The bug occurs when a My Things inventory folder has a large number of items in it, with 256 items per folder being a safe limit. At this point we believe this does not affect clothing items. The bug can make it impossible for you to log on, and although Customer Service can repair this, it's better to avoid the issue until we can resolve it. If you have more than 256 items in a single folder, you run the risk of encountering this problem.
To keep from seeing this bug, simply organize your folders to hold less than 256 items each.